Electrochemical method for providing hydrogen using ammonia and ethanol

ABSTRACT

An electrochemical method for providing hydrogen using ammonia, ethanol, or combinations thereof, comprising: forming an anode comprising a layered electrocatalyst, the layered electrocatalyst comprising at least one active metal layer deposited on a carbon support; providing a cathode comprising a conductor; disposing a basic electrolyte between the anode and the cathode; disposing a fuel within the basic electrolyte; and applying a current to the anode causing the oxidation of the fuel, forming hydrogen at the cathode.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority to the provisional applicationhaving application Ser. No. 60/916,222, which was filed on May 4, 2007;and to the provisional application having the application Ser. No.60/974,766, which was filed on Sep. 24, 2007. The present application isa continuation-in-part of the PCT application PCT/US2006/017641, whichwas filed on May 8, 2006 and in turn claimed priority to the provisionalapplication having application Ser. No. 60/678,725, which was filed onMay 6, 2005; and is a continuation-in-part of the non-provisionalapplication having the application Ser. No. 10/962,894, which was filedon Oct. 12, 2004 and issued on Feb. 3, 2009 as U.S. Pat. No. 7,485,211,and in turn claimed priority to the provisional application havingapplication Ser. No. 60/510,473, which was filed on Oct. 10, 2003, theentirety of which are incorporated herein by reference.

FIELD

The present embodiments relate to an electrochemical method forproviding hydrogen using ammonia, ethanol, or combinations thereof.

BACKGROUND

A need exists for an electrochemical method that incorporates use of anelectrochemical cell able to oxidize ammonia, ethanol, or combinationsthereof in alkaline media continuously.

A further need exists for an electrochemical method that utilizes anelectrode having a unique layered electrocatalyst that overcomes thepositioning of the electrode due to surface blockage.

A need also exists for an electrochemical method that utilizes a layeredelectrocatalyst with a carbon support that provides a hard rate ofperformance for the carbon support.

The present embodiments meet these needs.

SUMMARY OF THE INVENTION

According to an embodiment of the invention, an electrochemical methodfor producing hydrogen by applying an electric current to ammonia,ethanol, or combinations thereof, causing a reaction is provided. Themethod includes providing an anode comprising a layered electrocatalyst,providing a cathode comprising a conductor, disposing a basicelectrolyte between the anode and the cathode, flowing a fuel to thebasic electrolyte and applying an electric current to the anode causingoxidation of the fuel, evolving hydrogen at the cathode. The layeredelectrocatalyst includes a carbon support integrated with a conductivemetal; at least one active metal layer at least partially deposited onthe carbon support, wherein the at least one active metal layer isactive to ethanol, ammonia, or combinations thereof, and wherein the atleast one active metal layer has a thickness ranging from 10 nm to 10microns.

According to another embodiment of the invention, a method for surfacebuffered, assisted electrolysis of water is provided. The methodincludes providing an anode comprising a layered electrocatalyst,providing a cathode comprising a conductor, disposing an aqueous basicelectrolyte comprising water between the anode and the cathode,disposing a buffer solution within the aqueous basic electrolyte, andapplying an electric current to the anode causing oxidation of thewater, evolving hydrogen at the cathode. The layered electrocatalystincludes a carbon support integrated with a conductive metal; at leastone active metal layer at least partially deposited on the carbonsupport, wherein the at least one active metal layer is active to atarget species; and at least one second metal layer deposited on thecarbon support, wherein the at least one second metal layer is active toOH adsorption and inactive to the target species, and wherein the atleast one active metal layer has a thickness ranging from 10 nm to 10microns.

According to yet another embodiment, a method for open circuitelectrolysis of water is provided. The method includes providing ananode comprising a layered electrocatalyst, providing a cathodecomprising a conductor, disposing an aqueous basic electrolytecomprising water between the anode and the cathode, and disposing abuffer solution within the aqueous basic electrolyte, thereby causingoxidation of the basic electrolyte to evolve hydrogen at the cathodewhile producing water at the anode. The layered electrocatalyst includesa carbon support integrated with a conductive metal; at least one activemetal layer at least partially deposited on the carbon support, whereinthe at least one active metal layer is active to a target species, andwherein the at least one active metal layer has a thickness ranging from10 nm to 10 microns; and at least one second metal layer deposited onthe carbon support, wherein the at least one second metal layer isactive to OH adsorption and inactive to the target species, and whereinthe at least one active metal layer has a thickness ranging from 10 nmto 10 microns.

BRIEF DESCRIPTION OF THE DRAWINGS

The detailed description will be better understood in conjunction withthe accompanying drawings as follows:

FIG. 1 depicts an embodiment of an electrochemical cell useable with thepresent method.

FIG. 2 depicts an exploded view of an embodiment of the anelectrochemical cell stack useable with the present method.

FIG. 3 shows adsorption of OH on a Platinum cluster.

FIG. 4 shows experimental results of the electro-oxidation of ammonia ona Pt electrode, using a rotating disk electrode.

FIG. 5 shows results of microscopic modeling of the electro-adsorptionof OH, indicating that if the sites were available, the adsorption of OHwould continue producing higher oxidation currents

FIG. 6 shows a representation of the electro-oxidation mechanism ofammonia on a Pt electrode. As NH3 reaches the Pt surface it competeswith the OH″ electro-adsorption. Since the Electro-adsorption of OH″ isfaster on Pt the active sites of the electrode get saturated with the OHadsorbates causing deactivation of the electrode.

FIG. 7 shows a schematic representation of the procedure used toincrease the electronic conductivity of the carbon fibers during platingand operation.

FIG. 8 shows SEM photographs of the carbon fibers before plating andafter plating.

FIG. 9 shows cyclic voltammetry performance of 1M Ammonia and 1M KOHsolution at 25° C., comparing the performance of the carbon fiberelectrodes with different compositions.

FIG. 10 shows cyclic voltammetry performance of 1M Ammonia and 1M KOHsolution at 25° C., comparing the loading of the electrode, with lowloading 5 mg of total metal/cm of carbon fiber and high loading 10 mg ofmetal/cm of carbon fiber.

FIG. 11 shows cyclic voltammetry performance of 1M Ammonia and 1M KOHsolution at 25° C., comparing differing electrode compositions at lowloading of 5 mg of total metal/cm of fiber. Electrode compositionsinclude High Rh, Low Pt (80% Rh, 20% Pt), and low Rh and high Pt (20%Rh, 80% Pt).

FIG. 12 shows cyclic voltammetry performance of 1M Ammonia and 1M KOHsolution at 25° C., with differing ammonia concentration, indicatingthat the concentration of NH3 does not affect the kinetics of theelectrode.

FIG. 13 shows cyclic voltammetry performance of Effect of solution at25° C., with differing OH concentration, indicating that a higher theconcentration of OH causes faster kinetics.

FIG. 14 shows cyclic voltammetry performance of 1M ethanol and 1M KOHsolution at 25° C., indicating that the present electrochemical cell isalso useable for the continuous oxidation of ethanol.

FIG. 15 shows energy (a) and Power balance (b) of an ammoniaelectrochemical cell, exhibiting a low energy consumption compared tothat of a commercial water electrolyzer.

FIG. 16 depicts an embodiment of the steps of the present method.

The present embodiments are detailed below with reference to the listedFigures.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Before explaining the present apparatus in detail, it is to beunderstood that the apparatus is not limited to the particularembodiments and that it can be practiced or carried out in various ways.

The present embodiments relate to an electrochemical method forproviding hydrogen through a reaction from the oxidation of ammonia,ethanol, or combinations thereof.

Conventional hydrogen production is expensive, energy inefficient, andcreates unwanted byproducts.

The present electrochemical method provides the benefit of continuous,in-situ generation of hydrogen through the oxidation of ammonia,ethanol, or combinations thereof. The present electrochemical methodproduces hydrogen through the oxidation of both ammonia and ethanol,with a faradic efficiency of 100%. In both cases, the reaction thattakes place at the cathode is the reduction of water in alkaline medium,through the following reaction:2H₂O+2e ⁻→H₂+2OH⁻E⁰=0.82 V vs SHE

where SHE is a standard hydrogen electrode.

Hydrogen is the main fuel source for power generation using fuel cells,but the effective storage and transportation of hydrogen presentstechnical challenges. Current hydrogen production costs cause fuel celltechnology for distributed power generation to be economicallynon-competitive when compared to traditional oil-fueled power systems.Current distributed hydrogen technologies are able to produce hydrogenat costs of $5 to $6 per kg of H2. This high production cost is due inpart to high product separation/purification costs and high operatingtemperatures and pressures required for hydrogen production.

Using current technologies, hydrogen can be obtained by the partialoxidation, catalytic steam reforming, or thermal reforming of alcoholsand hydrocarbons. However, all of these processes take place at hightemperatures and generate a large amount of CO_(X) as byproducts, whichmust be removed from the hydrogen product. Most of these CO_(X)byproducts cause degeneration of fuel cell performance due to poisoningof the fuel cell catalysts. The removal of these byproducts from thefuel stream is complicated, bulky, and expensive.

Currently, the cleanest way to obtain pure hydrogen is by theelectrolysis of water. During the electrolysis of water electrical power(usually provided by solar cells) is used to break the water molecule,producing both pure oxygen and hydrogen. The disadvantage of thisprocess is that a large amount of electrical power is needed to producehydrogen. The theoretical energy consumption for the oxidation of wateris 66 W-h per mole of H^ produced (at 25° C.). Therefore, if solarenergy is used (at a cost of $0.2138/kWh), the theoretical cost ofhydrogen produced by the electrolysis of water is estimated to be $7 perkg of H2.

The present electrochemical method overcomes the costs and difficultiesassociated with the production of hydrogen, by enabling continuous,controllable evolution of hydrogen through the oxidation of plentifuland inexpensive feedstocks that include ammonia and/or ethanol.

Plating of carbon fibers, nano-tubes, and other carbon supports is adifficult task that is problematic due to the relatively low electronicconductivity of these materials. The low conductivity of carbon supportscan cause a poor coating of the surface of the support, which can beeasily removed. The electronic conductivity of carbon fibers and othercarbon supports decreases along the length from the electricalconnection. Therefore, the furthest point of contact to the electricconnection transfers a low current when compared with the closest pointto the electric contact.

The present electrochemical method advantageously utilizes a uniquelayered electrocatalyst that provides electrodes with uniform currentdistribution and enhanced adherence and durability of coating, andovercomes surface coverage affects, leaving a clean active surface areafor reaction.

It was believed that surface blockage caused during ammonia electrolysisin alkaline medium was due to the presence of elemental Nitrogen,according to the mechanism proposed by Gerisher:

$2\left( {{{NH}_{3} + M}\underset{k_{1}^{\prime}}{\overset{k_{1}}{\rightleftarrows}}{MNH}_{3}} \right)$$2\left( {{{MNH}_{3} + {OH}^{-}}\underset{k_{2}^{\prime}}{\overset{k_{2}}{\rightleftarrows}}{{MNH}_{2} + {H_{2}O} + {\mathbb{e}}^{-}}} \right)$$2\left( {{{MNH}_{2} + {OH}^{-}}\underset{k_{3}^{\prime}}{\overset{k_{3}}{\rightleftarrows}}{{MNH} + {H_{2}O} + {\mathbb{e}}^{-}}} \right)\mspace{11mu}({rds})$$\frac{1}{2}\left( {{{MNH} + {MNH}}\underset{k_{4}^{\prime}}{\overset{k_{4}}{\rightleftarrows}}{M_{2}N_{2}H_{2}}} \right)$$\frac{1}{2}\left( {{{M_{2}N_{2}H_{2}} + {2\;{OH}^{-}}}\underset{k_{5}^{\prime}}{\overset{k_{5}}{\rightleftarrows}}{{M_{2}N_{2}} + {2\; H_{2}O} + {2\;{\mathbb{e}}^{-}}}} \right)$${M_{2}N_{2}}\underset{k_{6}^{\prime}}{\overset{k_{6}}{\rightleftarrows}}{N_{2} + {2\; M}}$

Deactivation Reaction:

$2\left( {{{MNH} + {OH}^{-}}\underset{k_{4}^{\prime}}{\overset{k_{4}}{\rightleftarrows}}{{MN} + {H_{2}O} + {\mathbb{e}}^{-}}} \right)$where M represents an active site on the electrode.

The present electrochemical method incorporates the demonstrations oftwo independent methods indicating that the proposed mechanism byGerisher is not correct, and that OH needs to be adsorbed on theelectrode for the reactions to take place. Furthermore, the electrode isdeactivated by the OH adsorbed at the active sites.

Results from molecular modeling indicate that the adsorption of OH on anactive Pt site is strong (chemisorption) and can be represented by thefollowing reaction:Pt₁₀+OH⁻

Pt₁₀−OH_((ad)) +e ⁻

FIG. 3 shows a bond between a OH and a platinum cluster. The system wasmodeled using Density functional Methods. The computations wereperformed using the B3PW91 and LANL2DZ method and basis set,respectively. The binding energy for the Pt—OH cluster is high with avalue of −133.24 Kcal/mol, which confirms the chemisorption of OH on aPt cluster active site.

Additionally, results from microscopic modeling as well as experimentalresults on a rotating disk electrode (RDE) indicate that the adsorptionof OH is strong and responsible for the deactivation of the catalyst.

FIG. 4 compares the baseline of a KOH solution with the same solution inthe presence of OH. The curves indicate that the first oxidation peaksthat appear at about −0.7 V vs Hg/HgO electrode had to do with theelectro-adsorption of OH.

FIG. 5 shows a comparison of the predicted results (by microscopicmodeling) with the experimental results for the electro-adsorption ofOH. The results indicate that the model predicts the experimentalresults fairly well. Furthermore, an expression for the surface blockagedue to the adsorption of OH at the surface of the electrode wasdeveloped (notice that the active sites for reaction theta decay withthe applied potential due to adsorbates). If the surface were clean (seeresults model without coverage), the electro-adsorption of OH wouldcontinue even at higher potentials, and would occur more rapidly.

Compiling the experimental results with the modeling results, thefollowing mechanism for the electro-oxidation of ammonia in alkalinemedium is proposed: First the adsorption of OH takes place. As theammonia molecule approaches the electrode, it is also adsorbed on thesurface. Through the oxidation of ammonia, some OH adsorbates arereleased from the surface in the form of water molecules. However, sincethe adsorption of OH is stronger, and the OH ions move faster to thesurface of the electrode, they are deactivated, increasing potential.There will be a competition on the electrode between the adsorption ofOH and NH3.

The results of the mechanism are summarized on the proposed reactionsgiven below, as well as FIG. 6.Pt₁₀+OH⁻

Pt₁₀−OH⁻ _((ad))  (1)2Pt₁₀+2NH₃

2Pt₁₀−NH_(3(ad))  (2)Pt₁₀−NH_(1(ad))+Pt₁₀−OH⁻ _((ad))

Pt₁₀−NH_(2(ad))+Pt₁₀+H₂O+e ⁻  (3)Pt₁₀−NH_(2(ad))+Pt₁₀−OH⁻ _((ad))

Pt₁₀−NH_((ad))+Pt₁₀+H₂O+e ⁻  (4, rds)Pt₁₀−NH_((ad))+Pt₁₀−OH⁻ _((ad))

Pt₁₀−N_((ad))+Pt₁₀+H₂O+e ⁻  (5)2Pt₁₀−N_((ad))

Pt₁₀−N_(3(ad))+Pt₁₀  (6)Pt₁₀−NH_(2(ad))

Pt₁₀+N_(2(ad))  (7)

This mechanism can be extended to the electro-oxidation of otherchemicals in alkaline solution at low potentials (negative vs. standardhydrogen electrode (SHE)). For example, the mechanism has been extendedto the electro-oxidation of ethanol. The proposed mechanism clearlydefines the expectations for the design of better electrodes: thematerials used should enhance the adsorption of NH3 and/or ethanol, orother chemicals of interest. The proposed mechanism can also enhance theelectrolysis of water in alkaline medium. Through a combination of atleast two materials, one material more likely to be adsorbed by OH thanthe other, active sites are left available for the electro-oxidation ofthe interested chemicals, such as NH₃ and/or ethanol.

Significant current densities can be obtained from the oxidation ofammonia on active metals, but such electrodes are far less reversiblethan those used by the present electrochemical method. Similar casesoccur with the electro-oxidation of ethanol in alkaline medium.Furthermore, the activation of the electrodes is limited by surfacecoverage. The present electrochemical method overcomes the problems ofreversibility as well as deactivation.

The present electrochemical method includes the step of forming an anodethat includes a layered electrocatalyst.

The layered electrocatalyst includes at least one active metal layerdeposited on a carbon support. The carbon support can be integrated witha conductive metal, such as titanium, tungsten, nickel, stainless steel,or other similar conductive metals.

It is contemplated that the conductive metal integrated with the carbonsupport can have an inability or reduced ability to bind with metalplating layers used to form the layered electrocatalyst.

Active metal layers can include rhodium, rubidium, iridium, rhenium,platinum, palladium, copper, silver, gold, nickel, iron, or combinationsthereof.

The active metal layer is contemplated to have a strong affinity for theoxidation of ammonia, ethanol, or combinations thereof. The second metallayer is contemplated to have a strong affinity for hydroxide. Theaffinities of the layers enhance the electronic conductivity of thecarbon support.

Carbon supports can include carbon fibers, carbon tubes, carbonmicrotubes, carbon microspheres, carbon sheets, carbon nanotubes, carbonnanofibers, or combinations thereof. For example, groups of carbonnanofibers bound in clusters of 6,000, wound on titanium, nickel, carbonsteel, or other similar metals, could be used as a carbon support.

Carbon fibers can include woven or non-woven carbon fibers, that arepolymeric or other types of fibers. For example, a bundle ofpolyacrylonitrile carbon fibers could be used as a carbon support. Solidor hollow nano-sized carbon fibers, having a diameter less than 200nanometers, can also be useable. Bundles of 6000 or more carbon fibersare contemplated, having an overall diameter up to or exceeding 7micrometers.

Carbon microspheres can include nano-sized Buckyball supports, such asfree standing spheres of carbon atoms having plating on the inside oroutside, having a diameter less than 200 nanometers. Crushed and/orgraded microspheres created from the grinding or milling of carbon, suchas Vulcan 52, are also useable.

Carbon sheets can include carbon paper, such as that made by Toray™,having a thickness of 200 nanometers or less. Useable carbon sheets canbe continuous, perforated, or partially perforated. The perforations canhave diameters ranging from 1 to 50 nanometers.

Carbon tubes can include any type of carbon tube, such as nano-CAPP ornano-CPT, carbon tubes made by Pyrograf®, or other similar carbon tubes.For example, carbon tubes having a diameter ranging from 100 to 200nanometers and a length ranging from 3,000 to 100,000 nanometers couldbe used.

In an embodiment, one or more second metal layers can also be depositedon the carbon support. The second metal layers can include additionalactive metal layers, or layers of different metals.

The second metal layer can include platinum, iridium, or combinationsthereof. The ratio of platinum to iridium can range from 99.99:0.01 to50:50. In an embodiment, the ratio of platinum can range from 95:5 to70:30. In other embodiments, the ratio of platinum to iridium can rangefrom 80:20 to 75:25.

Formation of the anode can include using sputtering, electroplating,such as use of a hydrochloric acid bath, vacuum electrodeposition, orcombinations thereof, to deposit metal layers on the carbon support.

Each layer can be deposited on the carbon support in a thickness rangingfrom 10 nanometers to 10 microns. For example, a loading of at least 2mg/cm for each layer can be provided to a carbon fiber support, whileboth layers can provide a total loading ranging from 4 mg/cm to 10mg/cm.

Each layer can wholly or partially cover the carbon support. Each layercan be perforated. Each layer can have regions of varying thickness.

It is contemplated that the thickness and coverage of each layer can bevaried to accommodate the oxidation of a specified feedstock. Forexample, a feedstock having a 1M concentration of ammonia could beoxidized by an electrode having a layer that is 0.5 microns in thicknessat a rate of 100 mA/cm^2.

The strong activity of ammonia and/or ethanol of the electrocatalystused in the present electrochemical method, even with low ammoniaconcentrations, is useful in processes for removing ammonia fromcontaminated effluents. Accordingly, the electrocatalysts describedherein can be used to oxidize the ammonia contamination in thecontaminated effluent. An electrolytic cell may be prepared which usesat least one electrode comprising the layered electrocatalyst describedherein to oxidize ammonia contaminants in effluents. The effluent may befed as a continuous stream, wherein the ammonia is electrochemicallyremoved from the effluent, and the purified effluent is released orstored for other uses.

A cathode that includes a conductor is also provided. The cathode caninclude carbon, platinum, rhenium, palladium, nickel, Raney Nickel,iridium, vanadium, cobalt, iron, ruthenium, molybdenum, or combinationsthereof.

A basic electrolyte is disposed between the anode and the cathode. Thebasic electrolyte can include any alkaline electrolyte that iscompatible with the layered electrocatalyst, does not react with ammoniaor ethanol, and has a high conductivity.

The basic electrolyte can include any hydroxide donor, such as inorganichydroxides, alkaline metal hydroxides, or alkaline earth metalhydroxides. In an embodiment the basic electrolyte can include potassiumhydroxide, sodium hydroxide, or combinations thereof.

The basic electrolyte can have a concentration ranging from 0.1 M to 7M.In an embodiment, the basic electrolyte can have a concentration rangingfrom 3M to 7M.

A fuel is disposed within the basic electrolyte. The fuel can includeammonia, ethanol, or combinations thereof. In an embodiment, theammonia, ethanol, or combinations thereof can have a concentrationranging from 0.01 M to 5M. In other embodiments, the concentration ofammonia, ethanol, or combinations thereof, can range from 1M to 2M.

The present electrochemical method is useable with only trace amounts ofammonia and/or ethanol. Further, the present electrochemical method isuseable with ammonia and/or ethanol individually or simultaneously,thereby enabling the present method to accommodate a large variety offeedstocks.

An electric current is then applied to the anode, such as through use ofa power generation system, solar panels, alternate or direct currentsources, wind power sources, fuel cells, batteries, other similar powersources, or combinations thereof, causing oxidation of the fuel, forminghydrogen at the cathode. The electric current or current density can becontrolled, such as by using controller, to control the output ofhydrogen.

In an embodiment, the present electrochemical method can includeregulating the electric current to maintain the voltage of the reactionbelow one volt.

The present electrochemical method can also include placing a membraneor separator between the anode and cathode. The membrane/separator canbe selectively permeable to hydroxide and can include polypropylene,Teflon or other polyamides, fuel-cell grade asbestos, other similarpolymers, or combinations thereof.

The present embodiments also relate to a method for surface buffered,assisted electrolysis of water, which is also useable to producehydrogen.

An anode is formed, having a layered electrocatalyst, as describedpreviously. The layered catalyst includes both an active metal layer andat least a second metal layer deposited on a carbon support. A cathodethat includes a conductor is also provided.

An aqueous basic electrolyte, that includes water, is disposed betweenthe anode and the cathode.

A buffer solution is disposed within the aqueous basic electrolyte. Thebuffer solution can include ammonia, ethanol, propanol, or combinationsthereof. The concentration of the buffer solution can range from 1 ppmto 100 ppm. It is contemplated that only trace amounts of the buffersolution are necessary to assist the electrolysis of the water.

An electric current is then applied to the anode, causing oxidation ofthe water within the aqueous basic electrolyte, forming hydrogen at thecathode.

The electric current can be controlled to regulate the hydrogen output.It is also contemplated that the electric current can be regulated tomaintain a voltage of one volt or less.

The present embodiments further relate to a method for open circuitelectrolysis of water.

An anode is formed, having a layered electrocatalyst, as describedpreviously. The layered catalyst includes both an active metal layer andat least a second metal layer deposited on a carbon support. A cathodethat includes a conductor is also provided.

An aqueous basic electrolyte that includes water is disposed between theanode and cathode.

A buffer solution, which can include trace quantities of ammonia,ethanol, propanol, or combinations thereof, as described previously, isthen disposed within the aqueous basic electrolyte.

The addition of the buffer solution, in the presence of the basicelectrolyte and differing metals of the layered electrocatalyst, causesoxidation of the basic electrolyte to produce hydrogen at the cathode,while producing water at the anode.

The present electrochemical method contemplates use of anelectrochemical cell that incorporates the described layeredelectrocatalyst.

The electrochemical cell includes a first electrode formed from thelayered electrocatalyst.

The layered electrocatalyst includes at least one active metal layerdeposited on a carbon support. In an embodiment, the layeredelectrocatalyst can further include at least one second metal layerdeposited on the carbon support.

In a contemplated embodiment, the second metal layer can be a secondlayer of an active metal, such that the layered electrocatalyst includestwo active metal layers deposited on the carbon support. The thicknessof each metal layer can be varied.

The present electrochemical cell can thereby be customized to meet theneeds of users. For example, a first user may need to generate hydrogenfor fuel from the rapid oxidation of ethanol, while a second user mayneed to remove ammonia from a fixed volume of water for purificationpurposes.

FIG. 7 shows a schematic representation of the procedure used toincrease the electronic conductivity of the carbon fibers during plating(and also during the operation of the electrode). The fibers werewrapped on a titanium gauze, and were therefore. in electric contactwith the metal at different points. This improvement allowed an easy andhomogenous plating of the fibers at any point. The electronicconductivity at any point in the fiber was the same as the electronicconductivity of the Ti gauze.

The schematic for the construction of the electrode is also shown inFIG. 7. The plating procedure can include two steps: 1. First layerplating and 2. Second layer plating.

First layer plating includes plating the carbon support with materialsthat show a strong affinity for OH. Examples include, but are notlimited to Rh, Ru, Ni, and Pd. In one preferred embodiment, Rh is used.The first layer coverage should completely plate the carbon support. Insome embodiments, the first layer coverage is at least 2 mg/cm of carbonfiber to guarantee a complete plating of the carbon support. In otherembodiments, the first layer coverage can be 2.5 mg/cm, 3.0 mg/cm, 3.5mg/cm, or more.

Second layer plating includes plating the electrode with materials thathave a strong affinity for the oxidation of ammonia and/or ethanol.Examples include: Pt and Ir. Monometallic deposition and/or bimetallicdeposition of these materials can be performed. Ratios of Pt:Ir canrange from 100% Pt-0% Ir to 50% Pt-50% Ir.

Table I summarizes the plating conditions for the anode and the cathodeof the electrochemical cell. After plating the Rhodium, the electrode isweighted. The weight corresponds to the Rhodium loading. Then, thePlatinum is deposited on top of the Rhodium. After the procedure iscompleted, the electrode is measured again. The measurement willcorrespond to the total loading. The Platinum loading is obtained bysubtracting the total loading from the previous Rhodium measurement. Therelation of Platinum to Rhodium is then calculated as the percentage offixed loading. Because the loading depends on the length of the fiber,another measurement should be calculated. It is known that 10 cm offiber weights 39.1 mg, and because the weight of the fiber is known,then by proportionality, it can be known the length of the total fiberthat is being used in each electrode.

Table II summarizes the general conditions of a plating bath useable tocreate the electrodes. During the entire plating procedure, the solutionwas mixed to enhance the transport of the species to the carbon support.

Table III shows examples of some electrode compositions, lengths, andloadings of active metals.

TABLE 1 Conditions for Electro-plating Technique in the Deposition ofDifferent Metals on the Carbon Fibers and/or Carbon Nanotubes MetalPlated Rhodium (Rh) Platinum (Pt) Nickel (Ni) Position on the FirstSecond First Electrode Surface: Geometry: 2 × 2 cm² 2 × 2 cm² 4 × 4 cm²Conditions of the Total Volume: 250 ml Total Volume: 250 ml TotalVolume: 500 ml Solution: Composition of the 1M HC1 + Rhodium (III) 1MHC1 + Hydrogen Watt's Bath: Solution: Chloride (RhCl₃•XH₂O). RhHexachloroplatinate (IV) Nickel Sulphate (NiS0₄••6H₂0) 38.5-45.5%(different Hydrate, 99.9% 280 g/L Nickel Chloride compositions,depending on (H₂PtCl₆•6H₂O) (different (NiCl₂•6H₂O) 40 g/L Boric Acidloadings) compositions, depending (H₃BO₃) 30 g/L on loadings) CounterElectrode: Double Platinum Foil Purity Double Platinum Foil NickelSpheres (6 to 16 mm p.a.) 99.95% 20 × 50 × (0.004″) Purity 99.95% incontact with a Nickel Foil 20 × 50 × (0.004″) Electrode 99.9+% Purity(0.125 mm thick) Temperature: 70° C. 70° C. 45° C. Time: See AppliedCurrent See Applied Current 8 h approximately Loading: 5 mg/cm of Fiber5 mg/cm of Fiber Fixed Parameter, Between 6-8 mg/length of fiber AppliedCurrent: 100 mA (30 min) + 120 mA 40 mA (10 min) 4-60 (10 Stairs from100 mA, to 120 mA (30-60 min), depending on min) H-80 mA (10 min) 4- andthen to 140 mA loading 100 mA (1-2 h), depending on loading

TABLE 2 General Conditions of the Plating Bath Pretreatment Degreasingusing acetone Bath Type Chloride salts in HC1 Solution CompositionMetal/metal ratios varied for optimum deposit composition AppliedCurrent Galvanostatic (1 to 200 mA) Deposition Time Varied from 30minutes to several hours

TABLE 3 Examples of some Electrode Compositions and Loadings Ratio TotalLength, ID Composition Pt:Rh Loading, mg cm Mg/cm 2x2-1 21%Rh—79%Pt 3.81252.5 30.0 8.4 2x2-2 30%Rh—70%Pt 2.31 146.0 33.4 4.4 2x2-3 23%Rh—73%Pt3.44 151.5 30.5 5.0 2x2-4 30%Rh—70%Pt 2.32 308.8 31.3 9.9 2x2-5 Rh—Ir—Pt1.36 196.4 38.0 5.2 2x2-6 80%Rh—20%Pt 0.25 169.9 33.3 5.1 2x2-7 100%Rh —157.0 31.6 5.0 2x2-8 30%Rh—70%Pt 2.30 160.6 30.9 5.2 2x2-9 100%Pt —161.9 32.3 5.0

FIG. 8 shows a Scanning Electron Microscope photograph of the electrodebefore plating and after plating. A first layer of Rh was deposited onthe electrode to increase the electronic conductivity of the fibers andto serve as a free substrate for the adsorption of OH. (OH has moreaffinity for Rh than for Pt). A second layer consisting of Pt was platedon the electrode. The Pt layer did not cover all the Rh sites, leavingthe Rh surface to act as a preferred OH adsorbent.

FIG. 9 shows the cyclic voltammetry performance for theelectro-oxidation of ammonia on different electrode compositions. Noticethat the carbon fibers plated with only Rh are not active for thereaction, while when they are plated with only Pt, the electrode isactive but it is victim of poisoning. On the other hand, when theelectrode is made by plating in layers: first Rh is deposited and then asecond layer consisting of Pt is deposited, the electrode keeps theactivity. This is explained by the mechanism presented previously. FIG.9 demonstrates that the proposed method or preparation of the electrodeeliminates surface blockage difficulties.

FIG. 10 shows the effect of different total loading on theelectro-oxidation of ammonia. The results indicate that the catalystwith the lowest loading is more efficient for the electro-oxidation ofammonia. This feature results in a more economical process owing to alower expense related to the catalyst. Additional loading of thecatalyst just causes the formation of layers over layers that do nottake part in the reaction.

FIG. 11 illustrates the effect of the catalyst composition of theelectro-oxidation of ammonia in alkaline solution. There is not anotable difference in the performance of the electrode due to thecomposition of the electrode. This lack of difference is due to the factthat as long as a first layer of Rh is plated on the electrode, surfaceblockage will be avoided. Additional plating of Pt would cause thegrowth of a Pt island (see SEM picture, FIG. 8), which is not completelyactive in the whole surface.

FIG. 12 shows the effect of ammonia concentration on the performance ofthe electrode. The effect of ammonia concentration is negligible on theelectrode performance. This is due to the fact that the active Pt siteshave already adsorbed the NH3 needed for a continuous reaction. Due tothis feature, the present electrochemical cell is operable using onlytrace amounts of ammonia and/or ethanol.

FIG. 13 depicts the effect of the concentration of OH on theelectro-oxidation of ammonia. A larger concentration of OH causes afaster rate of reaction. The electrode maintains continuous activity,without poisoning, independent of the OH concentration.

FIG. 14 shows the evaluation of the electrode for the electro-oxidationof ethanol. Continuous electro-oxidation of ethanol in alkaline mediumis achieved without surface blockage. The present electrochemical cellis thereby useable to oxidize ethanol, as well as ammonia. The presentelectrochemical cell can further oxidize combinations of ammonia andethanol independently or simultaneously.

In an embodiment, the second electrode and first electrode can bothinclude a layered electrocatalyst.

The second electrode is contemplated to have an activity toward theevolution of hydrogen an alkaline media.

The first electrode, second electrode, or combinations thereof, caninclude rotating disc electrodes, rotating ring electrodes, cylinderelectrodes, spinning electrodes, ultrasound vibration electrodes, othersimilar types of electrodes, or combinations thereof.

The electrochemical cell further includes a basic electrolyte disposedin contact with each of the electrodes.

It is contemplated that the basic electrolyte can be present in a volumeand/or concentration that exceeds the stoichiometric proportions of theoxidation reaction, such as two to five times greater than theconcentration of ammonia, ethanol, or combinations thereof. In anembodiment, the basic electrolyte can have a concentration three timesgreater than the amount of ammonia and/or ethanol.

The electrochemical cell can include ammonia, ethanol, or combinationsthereof, which can be supplied as a fuel/feedstock for oxidation toproduce hydrogen.

The electrochemical cell can advantageously oxidize any combination ofammonia or ethanol, independently or simultaneously. A feedstockcontaining either ammonia, ethanol, or both ammonia and ethanol could bethereby be oxidized using the present electrochemical cell.Additionally, separate feedstocks containing ammonia and ethanol couldbe individually or simultaneously oxidized using the electrochemicalcell.

The ammonia, ethanol, or combinations thereof can be present inextremely small, millimolar concentrations, while still enabling theelectrochemical cell to be useable.

The ammonia and/or ethanol can be aqueous, having water, the basicelectrolyte, or another liquid as a carrier. For example, ammoniumhydroxide can be stored until ready for use, then fed directly into theelectrochemical cell.

It is also contemplated that ammonia can be stored as liquefied gas, ata high pressure, then combined with water and the basic electrolyte whenready for use. Ammonia could also be obtained from ammonium salts, suchas ammonium sulfate, dissolved in the basic electrolyte.

In an embodiment, the ammonia, ethanol, or combinations thereof can havea concentration ranging from 0.01 M to 5M. In other embodiments, theconcentration of ammonia, ethanol, or combinations thereof, can rangefrom 1M to 2M. At higher temperatures, a greater concentration ofammonia can be used.

The properties of the electrochemical cell, such as the thickness of theplating of the first electrode, can be varied to accommodate theconcentration of the feedstock.

The ability of the electrochemical cell to perform oxidation ofextremely small, millimolar concentrations of ammonia and/or ethanolenables the electrochemical cell to advantageously be used as adetector/sensor for ammonia and/or ethanol.

The ability of the electrochemical cell to perform oxidation of bothextremely small and large concentrations of ammonia and/or ethanolenables the electrochemical cell to advantageously accommodate a largevariety of feedstocks.

The oxidation of ammonia and/or ethanol by the electrochemical cell isendothermic. As a result, the electrochemical cell can be used to coolother adjacent or attached devices and equipment, such as a chargingbattery. Additionally, the heat from the adjacent devices and/orequipment can facilitate the efficiency of the reaction of theelectrochemical cell, creating a beneficial, synergistic effect.

The electrical current supplied to the electrochemical cell can varydepending on the properties of the cell and/or feedstock, based on theFaraday equation.

Contemplated current densities can range from 25 mA/cm^2 to 500 mA/cm^2.In other embodiments, the current densities can range from 50 mA/cm^2 to100 mA/cm^2. In still other embodiments, the current densities can rangefrom 25 mA/cm^2 to 50 mA/cm^2. Current densities can also range from 50mA/cm^2 to 500 mA/cm^2, from 100 mA/cm^2 to 400 mA/cm^2, or from 200mA/cm^2 to 300 mA/cm^2.

The electrical current can be provided from a power generation system,specifically designed to oxidize ammonia and/or ethanol. The powergeneration system is contemplated to be adjustable to large current,while providing power of one volt or less.

When electrical current is supplied to the electrochemical cell, it iscontemplated that the electrochemical cell can produce hydrogen,nitrogen, carbon dioxide, or combinations thereof. A controlled ammoniafeedstock reacts, in the alkaline medium, in combination with thecontrolled voltage and current, to produce nitrogen and hydrogen. Acontrolled ethanol feedstock reacts similarly, to produce carbon dioxideand hydrogen.

The electrochemical cell is contemplated to be operable at temperaturesranging from −50 degrees Centigrade to 200 degrees Centigrade. In anembodiment, the cell can be operable from 20 degrees Centigrade to 70degrees Centigrade. In another embodiment, the cell is operable from 60degrees Centigrade to 70 degrees Centigrade.

The cell can also be operable from 20 degrees Centigrade to 60 degreesCentigrade, from 30 degrees Centigrade to 70 degrees Centigrade, from 30degrees Centigrade to 60 degrees Centigrade, or from 40 degreesCentigrade to 50 degrees Centigrade.

It is contemplated that in an embodiment, a higher pressure can be used,enabling the electrochemical cell to be operable at higher temperatures.

The electrochemical cell is contemplated to be useable at pressuresranging from less than 1 atm to 10 atm.

A prototype system for the continuous electrolysis of ammonia and/orethanol in alkaline medium produced H2 continuously, with a faradicefficiency of 100%. The design of the cell was small (4×4 cm), andpermitted a significant production of H₂ at a small energy and powerconsumption. A cloud of H₂ was observed when generated at the cathode ofthe cell. The production of H₂ was massive, which demonstrates the useof the cell for in-situ H₂ production.

FIG. 15 shows the energy balance and the power balance on the ammoniaelectrolytic cell. The electrochemical cell outperforms a commercialwater electrolyzer. Both the energy and the power balance of the cellindicate that the cell could operate by utilizing some energy producedby a PEM H₂ fuel cell, and the system (ammonia electrolytic cell/PEMfuel cell) will still provide some net energy. This arrangement can beused to minimize hydrogen storage.

In one exemplary system, an excess of 480 kg of H₂ was produced per day.A total capital investment of $1,000,000 is needed for the constructionof the power system. A comparison of the economic analysis for theproduction of H₂ using the ammonia continuous electrolytic cell withcurrent state of the art technologies (natural gas reforming and waterelectrolysis) for distributed power has been performed. The continuousammonia electrolyzer can produce hydrogen at less than $2 per Kg.Compared to other technologies for in situ hydrogen production, savingsare substantial—using numbers provided by the National Academy ofScience, the continuous ammonia electrolyzer produced H2 about 20%cheaper than H2 can be produced using natural gas steam reforming, andabout 57% cheaper than using water electrolysis.

The electrochemical cell can be used to form one or more electrochemicalcell stacks, useable with the present electrochemical method, byconnecting a plurality of electrochemical cells in series, parallel, orcombinations thereof.

The electrochemical cell stack can include one or more bipolar platesdisposed between at least two adjacent electrochemical cells. Thebipolar plate can include an anode electrode, a cathode electrode, orcombinations thereof. For example, the bipolar plate could function asan anode for both adjacent cells, or the bipolar plate could have anodeelectrode materials deposited on a first side and cathode electrodematerials deposited on a second side.

The electrochemical cell stack can have any geometry, as needed, tofacilitate stacking, storage, and/or placement. Cylindrical, prismatic,spiral, tubular, and other similar geometries are contemplated.

In an embodiment, a single cathode electrode can be used as a cathodefor multiple electrochemical cells within the stack, each cell having ananode electrode.

In this embodiment, at least a first electrochemical cell would includea first electrode having a layered electrocatalyst, as describedpreviously, and a second electrode having a conductor.

At least a second of the electrochemical cells would then have a thirdelectrode that includes the layered electrocatalyst. The secondelectrode would function as the cathode for both the first and thesecond electrochemical cells.

In a contemplated embodiment, an electrochemical cell stack having aplurality of anode electrodes having the layered electrocatalyst and asingle cathode having a conductor can be used. For example, multipledisc-shaped anode electrodes can be placed in a stacked configuration,having single cathode electrode protruding through a central hole ineach anode electrode.

A basic electrolyte and ammonia, ethanol, or combinations thereof canthen be placed in contact with each of the plurality of anode electrodesand with the cathode electrode.

It is contemplated that this embodiment of the electrochemical cellstack can include a hydrogen-permeable membrane for facilitatingcollection of the hydrogen produced by the electrochemical cell stack.

The described embodiment of the electrochemical cell stack can furtherhave a fuel and current inlet in communication with each of theplurality of anodes, simultaneously, such as by extending through thecentral hole of each of the anodes.

Referring now to FIG. 1, FIG. 1 depicts a diagram of the components ofan electrochemical cell (10) useable with the present electrochemicalmethod.

The electrochemical cell (10) is depicted having a first electrode (11),which functions as an anode. The first electrode (11) is shown having alayered electrocatalyst (12) deposited on a carbon support (26). Thelayered electrocatalyst (12) is contemplated to include at least oneactive metal layer and can include at least one second metal layer.

The electrochemical cell (10) further depicts a second electrode (13)which is contemplated to include a conductor.

The electrodes (11, 13) are disposed within a housing (5), such that aspace exists between the electrodes (11, 13).

The electrochemical cell (10) is shown containing a basic electrolyte(36), such as sodium hydroxide or potassium hydroxide. Theelectrochemical cell (10) is also shown containing ammonia (20) andethanol (22) within the basic electrolyte (36). It is contemplated thatthe electrochemical cell (10) is useable for the continuous oxidation ofammonia or ethanol individually, or simultaneously.

Electrical current (34) from a power generation system (7) incommunication with the electrodes (11, 13) is applied to the firstelectrode (11) to cause the production of hydrogen (32) through theoxidation of the ammonia (20) and/or ethanol (22).

The depicted electrochemical cell (10) is shown having a hydrophilicmembrane (9) disposed between the electrodes (11, 13), which iscontemplated to selectively permit hydroxide exchange.

Referring now to FIG. 2, a diagram of an embodiment of anelectrochemical cell stack (16) useable with the present method isshown. The electrochemical cell stack (16) is shown having two ofelectrochemical cells, separated by a bipolar plate (3), which aredepicted in greater detail in FIG. 1.

The electrochemical cell stack (16) includes a first anode (11 a)adjacent a first end plate (92 a). A first gasket (94 a) and a secondgasket (94 b) are disposed between the first anode (11 a) and thebipolar plate (3).

The electrochemical cell stack (16) also includes a second anode (11 b)adjacent a second endplate (92 b) opposite the first end plate (92 a). Athird gasket (94 c) and a fourth gasket (94 d) are disposed between thesecond anode (11 b) and the bipolar plate (3).

The bipolar plate includes a cathode (13) disposed thereon. The cathode(13) is contemplated to function as a cathode for both the first anode(11 a) and the second anode (11 b).

While FIG. 2 depicts the electrochemical cell stack (16) including twoelectrochemical cells, it should be understood that any number ofelectrochemical cells, such as five cells or nine cells, can be stackedin a similar fashion, to produce a desired volume of hydrogen.

Referring now to FIG. 16, a diagram of an embodiment of the presentelectrochemical method is shown.

FIG. 16 depicts that an anode is formed by combining one or more activemetal layers and, optionally, a second metal layer, with a carbonsupport, such as by electrodeposition. (100). A cathode having aconductor is provided (102).

A basic electrolyte is disposed between the anode and cathode (104). Afuel is also provided within the basic electrolyte (106).

A current is then applied to the anode, such as through connection witha power source, causing oxidation of the fuel, forming hydrogen at thecathode (108).

While these embodiments have been described with emphasis on theembodiments, it should be understood that within the scope of theappended claims, the embodiments might be practiced other than asspecifically described herein.

1. An electrochemical method for producing hydrogen by applying anelectric current to ammonia, ethanol, or combinations thereof, causing areaction, the method comprising: providing an anode comprising a layeredelectrocatalyst, wherein the layered electrocatalyst comprises a carbonsupport integrated with a conductive metal; at least one active metallayer comprising platinum, or platinum and iridium at least partiallydeposited on the carbon support, wherein the at least one active metallayer is active to ethanol, ammonia, or combinations thereof, andwherein the at least one active metal layer is perforated and hasregions of varying thickness with at least one region having a thicknessranging from 10 nanometers to 10 microns; and at least one second metallayer comprising at least one of palladium, rhodium, or rutheniumdeposited on the carbon support, wherein the at least one second metallayer is active to OH adsorption and inactive to the target species, andwherein the at least one second metal layer has regions of varyingthickness with at least one region having a thickness ranging from 10nanometers to 10 microns; providing a cathode comprising a conductor;disposing a basic electrolyte between the anode and the cathode; flowinga fuel to the basic electrolyte; and applying an electric current to theanode causing oxidation of the fuel, evolving hydrogen at the cathode.2. The electrochemical method of claim 1, wherein the fuel is flowedcontinuously to the basic electrolyte.
 3. The electrochemical method ofclaim 1, further comprising the step of controlling the electric currentto control the output of the hydrogen.
 4. The electrochemical method ofclaim 1, further comprising the step of regulating the electric currentto maintain a voltage below one volt.
 5. The electrochemical method ofclaim 1, wherein the step of forming the anode comprises usingsputtering, electroplating, vacuum electrodeposition, or combinationsthereof to deposit the at least one active metal layer on the carbonsupport.
 6. The electrochemical method of claim 1, wherein the fuelcomprises ammonia, ethanol, or combinations thereof.
 7. Theelectrochemical method of claim 1, wherein the cathode comprises carbon,platinum, rhenium, palladium, nickel, iridium, vanadium, cobalt, iron,ruthenium, molybdenum, or combinations thereof.
 8. The electrochemicalmethod of claim 1, further comprising placing a membrane or separatorbetween the anode and the cathode.
 9. The electrochemical method ofclaim 1, wherein the electric current is provided using a powergeneration system, a solar panel, an AC power source, a DC power source,a wind power source, a fuel cell, a battery, other similar powersources, or combinations thereof.
 10. A method for surface buffered,assisted electrolysis of water, the method comprising: providing ananode comprising a layered electrocatalyst, wherein the layeredelectrocatalyst comprises: a carbon support integrated with a conductivemetal; at least one active metal layer comprising platinum, or platinumand iridium at least partially deposited on the carbon support, whereinthe at least one active metal layer is active to a target species, andwherein the at least one active metal layer is perforated and hasregions of varying thickness with at least one region having a thicknessranging from 10 nanometers to 10 microns; and at least one second metallayer comprising at least one of palladium, rhodium, or rutheniumdeposited on the carbon support, wherein the at least one second metallayer is active to OH adsorption and inactive to the target species, andwherein the at least one second metal layer has regions of varyingthickness with at least one region having a thickness ranging from 10nanometers to 10 microns; providing a cathode comprising a conductor;disposing an aqueous basic electrolyte comprising water between theanode and the cathode; disposing a buffer solution within the aqueousbasic electrolyte; and applying an electric current to the anode causingoxidation of the water, evolving hydrogen at the cathode.
 11. The methodof claim 10, wherein the buffer solution comprises ammonia, ethanol,propanol, or combinations thereof.
 12. The method of claim 11, whereinthe buffer solution has a concentration ranging from 1 ppm to 100 ppm.13. The method of claim 10, further comprising the step of controllingthe electric current to control the rate at which the hydrogen isevolved at the cathode.
 14. The method of claim 10, further comprisingthe step of regulating the electric current to maintain a voltage belowone volt.
 15. A method for open circuit electrolysis of water, themethod comprising: providing an anode comprising a layeredelectrocatalyst, wherein the layered electrocatalyst comprises: a carbonsupport integrated with a conductive metal; at least one active metallayer comprising platinum, or platinum and iridium at least partiallydeposited on the carbon support, wherein the at least one active metallayer is active to a target species, and wherein the at least one activemetal layer is perforated and has regions of varying thickness with atleast one region having a thickness ranging from 10 nanometers to 10microns; and at least one second metal layer comprising at least one ofpalladium, rhodium, or ruthenium deposited on the carbon support,wherein the at least one second metal layer is active to OH adsorptionand inactive to the target species, and wherein the at least one secondmetal layer has regions of varying thickness with at least one regionhaving a thickness ranging from 10 nanometers to 10 microns; providing acathode comprising a conductor; disposing an aqueous basic electrolytecomprising water between the anode and the cathode; and disposing abuffer solution within the aqueous basic electrolyte, thereby causingoxidation of the basic electrolyte to evolve hydrogen at the cathodewhile producing water at the anode.
 16. The method of claim 15, whereinthe buffer solution comprises ammonia, ethanol, propanol, orcombinations thereof.
 17. The method of claim 15, wherein the buffersolution has a concentration ranging from 1 ppm to 100 ppm.
 18. Anelectrochemical method for producing hydrogen by applying an electriccurrent to ammonia, ethanol, or combinations thereof, causing areaction, the method comprising: providing an anode comprising a layeredelectrocatalyst, wherein the layered electrocatalyst comprises aconductive support; at least one active metal layer comprising platinum,or platinum and iridium at least partially deposited on the conductivesupport, wherein the at least one active metal layer is active toethanol, ammonia, or combinations thereof, and wherein the at least oneactive metal layer is perforated and has regions of varying thicknesswith at least one region having a thickness ranging from 10 nanometersto 10 microns; and at least one second metal layer comprising at leastone of palladium, rhodium, or ruthenium deposited on the conductivesupport, wherein the at least one second metal layer is active to OHadsorption and inactive to the target species, and wherein the at leastone second metal layer has regions of varying thickness with at leastone region having a thickness ranging from 10 nanometers to 10 microns;providing a cathode comprising a conductor; disposing a basicelectrolyte between the anode and the cathode; flowing a fuel to thebasic electrolyte; and applying an electric current to the anode causingoxidation of the fuel, evolving hydrogen at the cathode.